The present invention relates generally to computer software. More particularly, it relates to data storage and databases.
In the field of data storage it is desirable to maintain records in a searchable database stored on a computer system. Databases are common means for storing various data, such as employee records, in a matrix-type format. A database may have multiple fields for different data elements. In the example of an employee records database, the fields may include an employee name, birth date, social security number, address, etc. To create a database, the user specifies fields and enters data for each entry in those fields.
Frequently, databases are customized by creating and fixing the number and type of database fields. This creates a problem when the database is required to expand by adding new fields. For example, with a database of employee records, a user might decide that additional information about employees is to be kept such as an employee""s starting date, type of vehicle, license plate number, etc.
An extensible database system is disclosed for storing data in a plurality of separate, lower-level databases. A top-level database is used to manipulate the data. The top-level database has a property dictionary that stores the names of properties in the database system, along with references to their locations. An initial database system is created having a plurality of separate databases, each of which may store one or more fields. References to each of the initial databases are stored in the dictionary. Thereafter, an added database may be used to add a property, or field, to the database system. The name of the added field is stored in the dictionary along with an address pointer or other reference to the memory location of the added database. To delete a field, the reference to that field is deleted from the property dictionary and the field data is removed from memory.